1. Field of the Invention
The present invention relates to air and vapor purification devices which function on the principle of adsorbency. In particular, this invention addresses the maintenance of such devices which require periodic regeneration or replacement of the adsorbent medium.
2. Description of the Prior Art
One of the more successful devices for cleansing air or vapor streams of undesirable chemical compounds is by means of a vapor adsorber. The objective of a vapor adsorber is to pass the air entering a closed volume through an adsorption column of particulate, activated carbon. Due to an adsorptive affinity for the carbon, certain compounds carried in the vapor phase by the air are held within the adsorption column.
This adsorption process is viewed as consumptive. As the process continues, the activated carbon charge attritionally saturates and loses its adsorptive capacity: a state known in the art as "spent." Although there are some vapor adsorber designs adapted for in situ regeneration of the carbon charge, most units require physical removal of the spent charge and replacement with freshly activated adsorbent. Such removal of the spent charge represents a difficult material handling problem.
A vapor adsorber charge mass may weigh from a few hundred pounds to several thousand. Charge consistency may be granular, pelletized or powdered. The generally practiced method of spent charge removal has been by vacuum truck whereby the charge is drafted from the adsorption vessel into a truck mounted container. When compatible with the adsorption unit operating site, the vacuum truck method is clean and effective. However, it is not always possible to locate a vapor adsorber unit on a truck accessible site. Moreover, a vacuum truck is an expensive, highly specialized vehicle maintained by relatively few vapor adsorber users. When needed, the equipment must be contracted from a third party and utility scheduled accordingly. If the vapor adsorber is used to protect an extremely sensitive environment, such equipment scheduling may become critical.
It is, therefore, an objective of the present invention to teach a clean and efficient method of removing a spent carbon charge from a vapor adsorber contact vessel using a minimum of light and inexpensive accessory equipment.
Another object of the present invention is to conveniently adapt a vapor adsorber unit as a vacuum sweeper for extraction of spent adsorbent charge from the unit contacting vessel.